Japan's whaling fleet has set sail for Antarctic waters where it will make its biggest catch in 20 years.

The boats will aim to catch nearly 1,000 whales over the coming months.

A global moratorium on commercial whaling has been in place since the 1980s, but Japan describes its programme as "scientific."

The hunting is condemned by most conservation groups on the grounds that it is inhumane, unnecessary and may harm fragile wildlife populations.

The fleet sailed on Tuesday from Shimonoseki port for the first year of a "research" programme called JARPA-2.

It envisages catching up to 935 minke whales and 10 fin whales during the southern hemisphere summer to "...monitor the Antarctic ecosystem, model competition among whale species... elucidate temporal and spatial changes in stock structure and improve the management procedure for the Antarctic minke whale stocks."

Doubling the catch

Minke whales reach about 10m at maturity (Image: Francois Gohier)

JARPA-2 replaces the JARPA-1 programme which took 440 Antarctic minkes each season.

In two years' time JARPA-2 will expand to include humpbacks, the favoured species for whale watchers.

Critics say this is commercial whaling in disguise, with meat obtained from the hunts sold for food in restaurants and schools.

Scientific objectives can be met through non-lethal methods, they say.

"Japan's announcement that it intends to kill more than twice as many minke whales and hunt two new species over the coming years provoked international outrage earlier this year," commented Philippa Brakes, a scientist with the Whale and Dolphin Conservation Society.

"The Japanese whalers know that the eyes of the world are upon them with an intensity that they have not experienced since the moratorium," she told the BBC News website.

In June, the annual meeting of the International Whaling Commission (IWC) passed a resolution condemning JARPA-2; but it has no power, as any member nation is empowered to run "scientific" programmes.

Sixty-three members of the IWC's Scientific Committee commented: "With the new proposal, Japan will increase its annual take... to levels approaching the annual commercial quotas for Antarctic minke whales that were in place prior to the moratorium.

"Consequently, we... feel unable to engage in a scientifically defensible process of review of the JARPA-2 proposal."

Although there is a global moratorium in commercial whaling dating from 1986, a number of countries continue to hunt.

Japan and Iceland run "scientific" programmes, while Norway lodged a formal objection to the moratorium which permits it to maintain an openly commercial operation.

A number of indigenous peoples are also allowed to hunt under tight restrictions.

The sheer volume of Japan's operations makes it the principal target for the wrath of conservation groups.

It also runs a scientific whaling programme in the north Pacific called JARPN, which this year took 100 sei whales, 100 minkes, 50 Bryde's whales and five sperm whales.

The Antarctic and Pacific programmes run at different times of the year, which conservationists allege is geared towards providing a constant supply of whale meat.

The JARPA-2 plans have created a flurry of activity in Australia and New Zealand, countries which were once highly active in the whaling industry but where hunting now provokes outrage, some of it connected to the burgeoning whale watching industry.

"We are calling on conservation minded governments to make the highest level representations from heads of state to the Prime Minister of Japan," said Philippa Brakes.

"We want them to urge him to address the burgeoning commercial hunts that Japan is conducting under the guise of scientific whaling."

There has been talk in Australian government circles of denying Japanese fishing vessels access to Australian ports or of taking legal action; but environment minister Ian Campbell, in comments to an Australian newspaper, appeared to rule out punitive measures.

"My strong view is that the actions that Australia is taking have the best chance of leading to a cessation of whaling altogether," he told The Age.

"We have tried very hard with both bilateral activity and diplomatic activity."

The reality is that on many other issues, Australia, New Zealand and Japan are closely allied, and whaling concerns are unlikely to figure as highly on the diplomatic agenda as security or trade.

Though Japan's hunting causes widespread concern in western countries, it is supported by a number of other governments; and as yet, the anti-hunt bloc does not have a mechanism through which it can force Japan to scale back or abandon its whaling operation.